The W3C Widgets specification covers the creation of HTML and JavaScript applications that only need to be downloaded once by a devise, and is great for mobile internet viewers. A look at how to create W3C widgets.

"HTML 5 supports contentEditable, by which I mean client-side in-browser "rich text" editing. All major browsers support this now, including Firefox 3, Safari 3, Opera 9, Google Chrome, and IE(since 5.5). Of course, the devil is in the details."